/*returnTop*/
p#back-to-top{
    position:fixed;
    display:none;
    bottom:15px;
    right:45px;
}
p#back-to-top a{
    text-align:center;
    text-decoration:none;
    color:#d1d1d1;
    display:block;
    width:64px;
    /*使用CSS3中的transition属性给跳转链接中的文字添加渐变效果*/
    -moz-transition:color 1s;
    -webkit-transition:color 1s;
    -o-transition:color 1s;
}
p#back-to-top a:hover{
    color:#979797;
}
p#back-to-top a span{
    background:transparent url(../img/icon/returntop.png) no-repeat 0px 2px;
    border-radius:6px;
    display:block;
    height:50px;
    width:50px;
    margin-bottom:5px;
    /*使用CSS3中的transition属性给<span>标签背景颜色添加渐变效果*/
    /*-moz-transition:background 1s;*/
    /*-webkit-transition:background 1s;*/
    /*-o-transition:background 1s;*/
}
#back-to-top a:hover span{
    background:transparent url(../img/icon/returntop.png) no-repeat -50px 2px;
}